Plasma chemical oxidation

With the plasma chemical oxidation process (alternatively "plasma electrolytic oxidation" or "micro-arc oxidation"), inorganic X-ray amorphous mixed oxide layers can be produced on the light metals aluminium, titanium, magnesium and their alloys, which contain non-stoichiometric compounds of electrolyte components with the substrate material in addition to oxidic compounds of the substrate material.

In addition to a special external power source, a galvanic tank is used to produce these layers. The component to be coated is placed in this tank as an anode. A Cr-Ni steel or a material of the same type as the anode can be used as the counter electrode. The surface of the component is converted into the oxidic form by applying a sufficiently high external electrical voltage; the direct reason for the oxide formation is the occurrence of microscopically small spark discharges on the component surfaces. At the same time, components of the special electrolytes are incorporated into the resulting oxide layer. This allows the properties of the layer produced to be specifically adapted or varied within wide limits using the electrical process parameters and the composition of the electrolytes. Source: INNOVENT e.V.